Mitel 3700 series dtmf decoder IC
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Has snyone worked with this device? It should be great for decoding
DTMF tones for use by the BS2 because it has a 1-wire sync.serial
output. Most of the other decoder IC`s i`ve played with all used a 4-
bit parallel bus to interface with the stamp, taking up 4 I/O pins in
the process. I`m having a problem though with the Shiftin command: it
only wil provide me with the first 3 bits of the 4 bit code from the
IC, and the MSB always seems to be a 1. Any ideas???
Thanks, Rob W
DTMF tones for use by the BS2 because it has a 1-wire sync.serial
output. Most of the other decoder IC`s i`ve played with all used a 4-
bit parallel bus to interface with the stamp, taking up 4 I/O pins in
the process. I`m having a problem though with the Shiftin command: it
only wil provide me with the first 3 bits of the 4 bit code from the
IC, and the MSB always seems to be a 1. Any ideas???
Thanks, Rob W
Comments
I tried to use the 3370, but ended up back with the 8870. Just as a curious
note, the distributor in Spain for Mitel/Zarlink sells thousands of 8870s,
but never sold ONE 3370 until I asked. I think the price is also higher. You
could try one device, which is the EDE300 (if my memory serves me right)
made by www.elabinc.com a parallel to serial converter, with 8-channel
input. This way you can use the 8870.
The problem with the 3370 is also that you still need three pins, one to
detect a valid tone, another to receive data, and another to clock out the
data. This only saves two pins in relation with the 8870.
All the best,
Mike
>
Mensaje original
> De: cirrusmtn@n... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=tawGOBQ0aO2aRWQfT22JMTdsbNbst7cr6psn7TKReXyxOKlHcozPs1vlvFRwnhYjLUIPO3BU_LVRw7tEri1m]cirrusmtn@n...[/url
> Enviado el: lunes, 08 de octubre de 2001 21:48
> Para: basicstamps@yahoogroups.com
> Asunto: [noparse][[/noparse]basicstamps] Mitel 3700 series dtmf decoder IC
>
>
> Has snyone worked with this device? It should be great for decoding
> DTMF tones for use by the BS2 because it has a 1-wire sync.serial
> output. Most of the other decoder IC`s i`ve played with all used a 4-
> bit parallel bus to interface with the stamp, taking up 4 I/O pins in
> the process. I`m having a problem though with the Shiftin command: it
> only wil provide me with the first 3 bits of the 4 bit code from the
> IC, and the MSB always seems to be a 1. Any ideas???
>
> Thanks, Rob W
>
>
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>Has snyone worked with this device? It should be great for decoding
>DTMF tones for use by the BS2 because it has a 1-wire sync.serial
>output. Most of the other decoder IC`s i`ve played with all used a 4-
>bit parallel bus to interface with the stamp, taking up 4 I/O pins in
>the process. I`m having a problem though with the Shiftin command: it
>only wil provide me with the first 3 bits of the 4 bit code from the
>IC, and the MSB always seems to be a 1. Any ideas???
I haven't used that part but at first glance, I'd check the clock edge
polarity. By that I mean: which clock edge shifts the data inside the
3700? It sounds like you might be sampling on the wrong edge.
dwayne
Dwayne Reid <dwayner@p...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax
Celebrating 17 years of Engineering Innovation (1984 - 2001)
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